Picked up some petrified wood from Rogers Mountain Oregon. They are small chunks that are found with rounded, smooth exteriors. Inside many have cores of translucent root beer colored agate. The wood itself is highly silicified and shows very well preserved cell structure. The story I've heard is that it was a raft of driftwood that was then replaced (petrified). My question is how do we know it wasn't normal petrified wood that eroded into a river or onto a beach and was worn after lithification by water action? Either way I think they're neat for their realistic wood appearance and gooey centers.

Very cool pieces. I think petrified driftwood would show an uneven wear pattern on the outside; areas where the cell structure and lines are crushed or warped from the wood being pushed up against other wood, rocks, shoreline, etc. or cracks from the repeated wet/dry. If the wear patterns are more or less consistent, then it would seem like the wood had been tumbled in a river post-petrification.